Question

In a certain population, body weights are normally distributed with a mean of 152 pounds and a standard deviation of 26 pounds. How many people must be surveyed if we want to estimate the percentage who weigh more than 180 pounds? Assume that we want 96% confidence that the error is no more than 4 percentage points.

Answer 1

Mean, = 152 pounds

Standard deviation, = 26 pounds

Margin of Error < 0.04

< 0.04

< 0.04

<

> 1334.905

Squaring both sides

n > 1781971.359

So At least 1781972 people must be surveyed.